1. Technical Field
The present disclosure relates to a high frequency unit in which a coaxial connector is fixed to a mounting plate that is supported by side walls of a shield case enclosing a circuit board to face the circuit board, and the coaxial connector being attached to or detached from an external connector.
2. Related Art
In this type of high frequency unit, an outer edge of a mounting plate extending from side walls of a shield case along a circuit board is supported by the side walls or a partition wall, so that a coaxial connector fixed to the mounting plate is stably supported. The partition wall is a metal plate partitioning a space on the circuit board and fixed to the side walls of the shield case. In addition, a high frequency circuit unit such as a tuner circuit is formed on the circuit board, and a core extending from the coaxial connector toward the circuit board is soldered to a connection land of the high frequency circuit unit (for example, refer to Japanese Patent No. 4020743).
In a technique disclosed in Japanese Patent No. 4020743, the entire outer edge (four sides) of the rectangular mounting plate is supported by the three side walls of the shield case and the partition wall. In this case, a longitudinal dimension of the mounting plate is the same as a longitudinal dimension of a longer side of the side wall of the shield case, so that the area of the mounting plate is large.
Also, a high frequency unit having a configuration in which a coaxial connector is fixed to a mounting plate with a relatively smaller area has been widely used. In this configuration, an outer edge of the mounting plate is supported by one or two adjacent side walls of a shield case and a partition wall, and thus the mounting plate has a narrow width that is slightly greater than an outer diameter of the coaxial connector.
In addition, an open end of the shield case at which the mounting plate is disposed is generally covered by a sheet metal cover provided with a through-hole through which a coaxial connector penetrates. The sheet metal cover covers the shield case while overlapping with the mounting plate and is fitted to the side walls of the shield case.
However, in this type of high frequency unit, when an external connector is attached to or detached from the coaxial connector fixed to the mounting plate, a relatively high bending stress is exerted on the mounting plate. In the technique disclosed in Japanese Patent No. 4020743, the entire periphery of the outer edge of the rectangular mounting plate is supported by the side walls of the shield case and the partition wall, so that there is a small possibility that the mounting plate is significantly deformed when attached to or detached from the external connector. However, due to the large area of the mounting plate, a little deformation thereof cannot be avoided. In addition, when the mounting plate is deformed when attached to or detached from the external connector, an external force causing a core of the coaxial connector to push or pull the circuit board occurs, and there was a concern that a junction of the core and the circuit board may be broken down.
In addition, in the case of the existing high frequency unit in which the outer edge of the mounting plate is supported by one or two adjacent side walls of the shield case and the partition wall, peripheral portions that are easily deformed exist at the outer edge of the mounting plate. Therefore, there was a concern that, when attaching or detaching the external connector, the mounting plate is deformed and the junction of the core of the coaxial connector and the circuit board may be broken down.
It is desirable to provide a high frequency unit capable of suppressing deformation of a mounting plate which needs to be concerned when attaching or detaching an external connector, at low cost and high reliability of a connection between a core of a coaxial connector and a circuit board.